/* Site 1 - Root: Classic Telegram Blue, Centered Hero, Card Grid */
:root {
  --primary: #0088cc;
  --primary-dark: #006699;
  --primary-light: #e8f6fc;
  --accent: #2aabee;
  --text: #1a2b3c;
  --text-muted: #5a6a7a;
  --bg: #f5f9fc;
  --white: #ffffff;
  --border: #d4e5f0;
  --success: #31b545;
  --radius: 12px;
  --shadow: 0 4px 20px rgba(0, 136, 204, 0.1);
  --font: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
}
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }
img { max-width: 100%; }
.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

/* Nav - solid top bar */
.site-header {
  background: var(--white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 1px 8px rgba(0,0,0,0.04);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text);
}
.logo svg { width: 36px; height: 36px; }
.nav-links { display: flex; gap: 8px; list-style: none; }
.nav-links a {
  display: block;
  padding: 8px 16px;
  border-radius: 8px;
  color: var(--text-muted);
  font-weight: 500;
  transition: background 0.2s, color 0.2s;
}
.nav-links a:hover { background: var(--primary-light); color: var(--primary); }
.nav-links a.active {
  background: var(--primary);
  color: var(--white);
}
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 8px; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border: none;
  border-radius: 10px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
}
.btn:hover { transform: translateY(-1px); }
.btn:disabled { opacity: 0.7; cursor: wait; transform: none; }
.btn-primary {
  background: var(--primary);
  color: var(--white);
  box-shadow: 0 4px 14px rgba(0, 136, 204, 0.35);
}
.btn-primary:hover { background: var(--primary-dark); }
.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}
.btn-outline:hover { background: var(--primary-light); }
.btn-lg { padding: 16px 36px; font-size: 1.1rem; }
.btn-block { width: 100%; }

@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }

/* Hero - centered */
.hero {
  text-align: center;
  padding: 80px 0 70px;
  background: linear-gradient(180deg, #dff2fb 0%, var(--bg) 100%);
}
.hero-badge {
  display: inline-block;
  background: var(--white);
  color: var(--primary);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 20px;
  border: 1px solid var(--border);
}
.hero h1 {
  font-size: 2.6rem;
  line-height: 1.25;
  margin-bottom: 18px;
  color: var(--text);
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
}
.hero-desc {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto 32px;
}
.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero-visual {
  margin-top: 48px;
  display: flex;
  justify-content: center;
}
.hero-visual svg { width: 200px; height: 200px; }

/* Sections */
.section { padding: 64px 0; }
.section-alt { background: var(--white); }
.section-title {
  text-align: center;
  font-size: 1.9rem;
  margin-bottom: 12px;
}
.section-sub {
  text-align: center;
  color: var(--text-muted);
  max-width: 640px;
  margin: 0 auto 40px;
}

/* Feature cards */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.feature-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
  box-shadow: var(--shadow);
  transition: border-color 0.2s;
}
.feature-card:hover { border-color: var(--accent); }
.feature-icon {
  width: 48px;
  height: 48px;
  background: var(--primary-light);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}
.feature-icon svg { width: 26px; height: 26px; color: var(--primary); }
.feature-card h3 { font-size: 1.15rem; margin-bottom: 10px; }
.feature-card p { color: var(--text-muted); font-size: 0.95rem; }

/* Platform download */
.platform-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.platform-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
}
.platform-card svg { width: 40px; height: 40px; margin-bottom: 14px; color: var(--primary); }
.platform-card h3 { margin-bottom: 8px; font-size: 1.1rem; }
.platform-card p { color: var(--text-muted); font-size: 0.875rem; margin-bottom: 16px; }

/* Detail blocks */
.detail-block {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
  margin-bottom: 56px;
}
.detail-block.reverse { direction: rtl; }
.detail-block.reverse > * { direction: ltr; }
.detail-block h2 { font-size: 1.5rem; margin-bottom: 14px; }
.detail-block p { color: var(--text-muted); margin-bottom: 12px; }
.detail-visual {
  background: var(--primary-light);
  border-radius: var(--radius);
  padding: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.detail-visual svg { width: 120px; height: 120px; color: var(--primary); }

/* Stats */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.stat-item {
  text-align: center;
  background: var(--white);
  border-radius: var(--radius);
  padding: 28px 16px;
  border: 1px solid var(--border);
}
.stat-num {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
  display: block;
  margin-bottom: 6px;
}
.stat-label { color: var(--text-muted); font-size: 0.9rem; }

/* Reviews */
.review-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.review-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}
.review-stars { color: #f5a623; margin-bottom: 10px; display: flex; gap: 2px; }
.review-stars svg { width: 16px; height: 16px; fill: currentColor; }
.review-card p { color: var(--text-muted); font-size: 0.95rem; margin-bottom: 14px; }
.review-user { font-weight: 600; font-size: 0.9rem; }

/* Compare table */
.compare-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}
.compare-table th, .compare-table td {
  padding: 14px 18px;
  text-align: center;
  border-bottom: 1px solid var(--border);
}
.compare-table th { background: var(--primary); color: var(--white); font-weight: 600; }
.compare-table th:first-child, .compare-table td:first-child { text-align: left; }
.compare-table tr:last-child td { border-bottom: none; }
.compare-table .yes { color: var(--success); font-weight: 600; }
.compare-table .no { color: #c0392b; }

/* FAQ */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
}
.faq-item summary {
  padding: 18px 24px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  font-size: 1.3rem;
  color: var(--primary);
  font-weight: 400;
}
.faq-item[open] summary::after { content: "−"; }
.faq-item .faq-answer {
  padding: 0 24px 20px;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  padding-top: 16px;
  margin: 0 24px 20px;
}

/* Download page */
.dl-hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: var(--white);
  padding: 60px 0;
  text-align: center;
}
.dl-hero h1 { font-size: 2.2rem; margin-bottom: 12px; }
.dl-hero p { opacity: 0.9; margin-bottom: 24px; max-width: 560px; margin-left: auto; margin-right: auto; }
.dl-meta { display: flex; gap: 24px; justify-content: center; flex-wrap: wrap; margin-bottom: 28px; font-size: 0.95rem; }
.dl-meta span { opacity: 0.95; }
.dl-hero .btn-primary {
  background: var(--white);
  color: var(--primary);
  box-shadow: 0 4px 20px rgba(0,0,0,0.15);
}
.dl-hero .btn-primary:hover { background: var(--primary-light); }

.install-steps { counter-reset: step; }
.install-step {
  display: flex;
  gap: 20px;
  margin-bottom: 28px;
  align-items: flex-start;
}
.install-step::before {
  counter-increment: step;
  content: counter(step);
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  background: var(--primary);
  color: var(--white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
}
.install-step h3 { margin-bottom: 6px; }
.install-step p { color: var(--text-muted); }

.changelog { max-width: 800px; margin: 0 auto; }
.changelog-item {
  border-left: 3px solid var(--primary);
  padding: 16px 0 16px 24px;
  margin-bottom: 8px;
}
.changelog-ver { font-weight: 700; color: var(--primary); }
.changelog-date { color: var(--text-muted); font-size: 0.875rem; margin-left: 12px; }
.changelog-item ul { margin-top: 8px; padding-left: 18px; color: var(--text-muted); }
.changelog-item li { margin-bottom: 4px; }

.req-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
}
.req-table th, .req-table td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
.req-table th { background: var(--primary-light); color: var(--text); }

.security-box {
  background: var(--primary-light);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  text-align: center;
}
.security-box h2 { margin-bottom: 12px; }
.security-box p { color: var(--text-muted); }

/* zh-cn article style */
.article-hero {
  padding: 56px 0 40px;
  text-align: center;
  background: var(--white);
  border-bottom: 1px solid var(--border);
}
.article-hero h1 { font-size: 2rem; margin-bottom: 14px; max-width: 700px; margin-left: auto; margin-right: auto; }
.article-hero p { color: var(--text-muted); max-width: 600px; margin: 0 auto; }
.article-body { max-width: 780px; margin: 0 auto; padding: 48px 20px; }
.article-body h2 { font-size: 1.4rem; margin: 36px 0 14px; color: var(--text); }
.article-body h3 { font-size: 1.15rem; margin: 24px 0 10px; }
.article-body p { margin-bottom: 14px; color: var(--text-muted); }
.article-body ul { margin: 12px 0 20px 24px; color: var(--text-muted); }
.article-body li { margin-bottom: 8px; }
.cta-box {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: var(--white);
  border-radius: var(--radius);
  padding: 40px;
  text-align: center;
  margin: 48px 0;
}
.cta-box h2 { color: var(--white); margin-bottom: 12px; }
.cta-box p { opacity: 0.9; margin-bottom: 24px; }
.cta-box a.btn {
  background: var(--white);
  color: var(--primary);
}

/* Footer */
.site-footer {
  background: #0d2137;
  color: #a8c0d4;
  padding: 40px 0 28px;
  margin-top: 0;
}
.footer-secure {
  text-align: center;
  padding: 14px;
  background: rgba(255,255,255,0.06);
  border-radius: 8px;
  margin-bottom: 20px;
  font-size: 0.95rem;
}
.footer-copy {
  text-align: center;
  font-size: 0.85rem;
  opacity: 0.8;
  line-height: 1.6;
}
.footer-nav {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-bottom: 20px;
  list-style: none;
}
.footer-nav a { color: #a8c0d4; }
.footer-nav a:hover { color: var(--white); }

@media (max-width: 900px) {
  .feature-grid, .review-grid { grid-template-columns: 1fr 1fr; }
  .platform-grid, .stats-row { grid-template-columns: 1fr 1fr; }
  .detail-block, .detail-block.reverse { grid-template-columns: 1fr; direction: ltr; }
  .hero h1 { font-size: 2rem; }
}
@media (max-width: 640px) {
  .nav-links { display: none; }
  .nav-links.open { display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0; background: var(--white); padding: 12px; border-bottom: 1px solid var(--border); }
  .nav-toggle { display: block; }
  .feature-grid, .review-grid, .platform-grid, .stats-row { grid-template-columns: 1fr; }
  .hero { padding: 48px 0 40px; }
  .hero h1 { font-size: 1.7rem; }
  .compare-table { font-size: 0.85rem; }
}